kitaev@213: /*
kitaev@213:  * Copyright (c) 2011 TMate Software Ltd
kitaev@213:  *  
kitaev@213:  * This program is free software; you can redistribute it and/or modify
kitaev@213:  * it under the terms of the GNU General Public License as published by
kitaev@213:  * the Free Software Foundation; version 2 of the License.
kitaev@213:  *
kitaev@213:  * This program is distributed in the hope that it will be useful,
kitaev@213:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
kitaev@213:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
kitaev@213:  * GNU General Public License for more details.
kitaev@213:  *
kitaev@213:  * For information on how to redistribute this software under
kitaev@213:  * the terms of a license other than GNU General Public License
kitaev@213:  * contact TMate Software at support@hg4j.com
kitaev@213:  */
kitaev@213: package org.tmatesoft.hg.internal;
kitaev@213: 
kitaev@213: import java.util.HashMap;
kitaev@213: 
kitaev@213: /**
kitaev@213:  * Instance pooling.
kitaev@213:  * 
kitaev@213:  * @author Artem Tikhomirov
kitaev@213:  * @author TMate Software Ltd.
kitaev@213:  */
kitaev@213: public class Pool<T> {
kitaev@213: 	private final HashMap<T,T> unify = new HashMap<T, T>();
kitaev@213: 	
kitaev@213: 	public T unify(T t) {
kitaev@213: 		T rv = unify.get(t);
kitaev@213: 		if (rv == null) {
kitaev@213: 			// first time we see a new value
kitaev@213: 			unify.put(t, t);
kitaev@213: 			rv = t;
kitaev@213: 		}
kitaev@213: 		return rv;
kitaev@213: 	}
kitaev@213: 	
kitaev@213: 	@Override
kitaev@213: 	public String toString() {
kitaev@213: 		StringBuilder sb = new StringBuilder();
kitaev@213: 		sb.append(Pool.class.getSimpleName());
kitaev@213: 		sb.append('<');
kitaev@213: 		if (!unify.isEmpty()) {
kitaev@213: 			sb.append(unify.keySet().iterator().next().getClass().getName());
kitaev@213: 		}
kitaev@213: 		sb.append('>');
kitaev@213: 		sb.append(':');
kitaev@213: 		sb.append(unify.size());
kitaev@213: 		return sb.toString();
kitaev@213: 	}
kitaev@213: }